4.4-stable review patch. If anyone has any objections, please let me know.
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From: Ming Lei ming.lei@redhat.com
commit 744889b7cbb56a64f957e65ade7cb65fe3f35714 upstream.
blk_queue_split() does respect this limit via bio splitting, so no need to do that in blkdev_issue_discard(), then we can align to normal bio submit(bio_add_page() & submit_bio()).
More importantly, this patch fixes one issue introduced in a22c4d7e34402cc ("block: re-add discard_granularity and alignment checks"), in which zero discard bio may be generated in case of zero alignment.
Fixes: a22c4d7e34402ccdf3 ("block: re-add discard_granularity and alignment checks") Cc: stable@vger.kernel.org Cc: Ming Lin ming.l@ssi.samsung.com Cc: Mike Snitzer snitzer@redhat.com Cc: Christoph Hellwig hch@lst.de Cc: Xiao Ni xni@redhat.com Tested-by: Mariusz Dabrowski mariusz.dabrowski@intel.com Signed-off-by: Ming Lei ming.lei@redhat.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sudip Mukherjee sudipm.mukherjee@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- block/blk-lib.c | 28 ++-------------------------- 1 file changed, 2 insertions(+), 26 deletions(-)
--- a/block/blk-lib.c +++ b/block/blk-lib.c @@ -43,8 +43,6 @@ int blkdev_issue_discard(struct block_de DECLARE_COMPLETION_ONSTACK(wait); struct request_queue *q = bdev_get_queue(bdev); int type = REQ_WRITE | REQ_DISCARD; - unsigned int granularity; - int alignment; struct bio_batch bb; struct bio *bio; int ret = 0; @@ -56,10 +54,6 @@ int blkdev_issue_discard(struct block_de if (!blk_queue_discard(q)) return -EOPNOTSUPP;
- /* Zero-sector (unknown) and one-sector granularities are the same. */ - granularity = max(q->limits.discard_granularity >> 9, 1U); - alignment = (bdev_discard_alignment(bdev) >> 9) % granularity; - if (flags & BLKDEV_DISCARD_SECURE) { if (!blk_queue_secdiscard(q)) return -EOPNOTSUPP; @@ -72,8 +66,8 @@ int blkdev_issue_discard(struct block_de
blk_start_plug(&plug); while (nr_sects) { - unsigned int req_sects; - sector_t end_sect, tmp; + unsigned int req_sects = nr_sects; + sector_t end_sect;
bio = bio_alloc(gfp_mask, 1); if (!bio) { @@ -81,28 +75,10 @@ int blkdev_issue_discard(struct block_de break; }
- /* - * Issue in chunks of the user defined max discard setting, - * ensuring that bi_size doesn't overflow - */ - req_sects = min_t(sector_t, nr_sects, - q->limits.max_discard_sectors); if (req_sects > UINT_MAX >> 9) req_sects = UINT_MAX >> 9;
- /* - * If splitting a request, and the next starting sector would be - * misaligned, stop the discard at the previous aligned sector. - */ end_sect = sector + req_sects; - tmp = end_sect; - if (req_sects < nr_sects && - sector_div(tmp, granularity) != alignment) { - end_sect = end_sect - alignment; - sector_div(end_sect, granularity); - end_sect = end_sect * granularity + alignment; - req_sects = end_sect - sector; - }
bio->bi_iter.bi_sector = sector; bio->bi_end_io = bio_batch_end_io;